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From "Kristian Waagan (JIRA)" <j...@apache.org>
Subject [jira] Commented: (DERBY-4771) Continue investigation of automatic creation/update of index statistics
Date Fri, 19 Nov 2010 12:23:14 GMT

    [ https://issues.apache.org/jira/browse/DERBY-4771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12933790#action_12933790
] 

Kristian Waagan commented on DERBY-4771:
----------------------------------------

Thanks Lily,

The invalidation request is still performed in IndexStatisticsDaemon, but not until after
all the statistics for a given table (for all the indexes of that table, that is) have been
generated.
As said, there are still some problem with the invalidation, since I have discovered that
it can "deadlock". The situation involves both database locks and Java monitors, so it is
not a regular database deadlock, and it will result in a timeout.

Regarding the value of the property, I can change that to 'log' in the next rev of the patch.
Note that the trace-property may be removed in the final version, I haven't decided yet. We
also have to decide what should be logged, and maybe consider adding multiple log levels to
control the amount of data written to the log.

Let me summarize what I think are the next most important steps:
 o testing! This will be easier once the code is committed to trunk, but we're not quite there
yet. I think the best way to test this is to run it with various applications, also some that
run for a longer period of time.
 o organization of the code; where to place the daemon, whether to introduce an interface,
whether to move daemon control out of the data dictionary.
 o tuning of table size boundaries for when the daemon kicks in

> Continue investigation of automatic creation/update of index statistics
> -----------------------------------------------------------------------
>
>                 Key: DERBY-4771
>                 URL: https://issues.apache.org/jira/browse/DERBY-4771
>             Project: Derby
>          Issue Type: Task
>          Components: SQL, Store
>    Affects Versions: 10.8.0.0
>            Reporter: Kristian Waagan
>            Assignee: Kristian Waagan
>         Attachments: derby-4771-1a-prototype_code_dump.diff, derby-4771-1a-prototype_code_dump.stat,
derby-4771-1b-prototype_code_dump.diff, derby-4771-2a-prototype_lcc_code_dump.diff, derby-4771-2b-prototype_lcc_code_dump.diff,
derby-4771-2c-prototype_lcc_code_dump.diff, derby-4771-2d-prototype_lcc_code_dump.diff, derby.log,
error-stacktrace.out, rjall.out, rjall.out, rjall.out, rjall.rar, rjone.out
>
>
> Work was started to improve Derby's handling of index statistics. This issue tracks further
discussion and work for this task.

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